Oral NEW ROUTES FOR PRODUCING NANOWIRES AND NANOTUBES AND THEIR PHYSICAL PROPERTIES

Nanochemistry fabrication methods have improved remarkably over the last few years. Among the different strategies developed to elaborate nanomaterials, the templating method is one of the most attractive as it has proven to be reliable for the synthesis of arrays of nanowires and nanotubules of desired composition, sizes and aspect ratios. Chemical and electrochemical techniques are used for synthesizing arrays of nanowires and nanotubes inside the voids spaces of nanoporous host materials. To date, most of the work in this area has entailed the use of two types of templates : track-etched polymer membranes and nanoporous aluminas. These two types of templates are produced at the lab-scale at the Materials Science Department at UCL and exhibit well-defined nanoporosity with geometrical parameters controllable to a large extent [1]. A variety of nanowired materials including noble metals, ferromagnets, superconductors, semimetals, oxydes, carbon nanotubes and conducting polymers have been fabricated via chemical and electrochemical techniques. Also, complex structures such as organic/inorganic nanocomposites and multilayers composed of ultra-thin layers of magnetic and non magnetic metals have ben successfully fabricated by this method [2]. The resulting cylinders have diameters ranging between 10 nm and a few microns, a smooth surface, and the controlled length can vary from few nanometers up to 20 micrometers. Arrays of vertically aligned and free standing nanowires can also be formed by the selective dissolution of the supported nanoporous media. Such nanowires systems are intrinsically scientifically interesting systems with a lot of potential applications in various areas.